题解 | 21年8月份练题总数
21年8月份练题总数
https://www.nowcoder.com/practice/b8f30b239b454ed490367b53ea95607d
select count(distinct device_id) as did_cnt, count(question_id) as question_cnt from question_practice_detail where month(date) = 8 and year(date) = 2021
注意用户id前面加distinct,因为用户有可能有重复的

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